Amazon memo reveals push for employees to use only Kiro, its in-house AI tool

Amazon has urged staff to prioritise its in-house AI coding tool Kiro over third-party options, stepping up efforts to strengthen the company’s position in the fast-moving market for software development assistants.

An internal memo viewed by Reuters told engineers to stop adopting new external AI coding tools and instead use Kiro, which Amazon launched in July. The company said it would continue supporting some existing external tools already in use but would not approve any further additions.

The memo, posted on Amazon’s internal news site, stated: “While we continue to support existing tools in use today, we do not plan to support additional third party, AI development tools.” It also emphasised the role of Amazon engineers in helping refine Kiro, saying their feedback would be used “to aggressively improve” the product.

The guidance effectively discourages employees from using rival tools such as OpenAI’s Codex, Anthropic’s Claude Code and AI startup Cursor. Reuters reported that this comes despite Amazon investing around $8 billion in Anthropic and signing a seven-year, $38 billion cloud-computing deal with OpenAI.

The move reflects Amazon’s push to dispel perceptions that it is lagging in AI development as competitors, including OpenAI and Google, ship products at pace. Kiro, built largely on variants of Anthropic technologies, is designed to generate website and app code from plain English instructions. It does not rely directly on Claude Code.

The memo was signed by senior executives Peter DeSantis, who oversees AWS utility computing, and Dave Treadwell, head of Amazon’s eCommerce Foundation. “We’re making Kiro our recommended AI-native development tool for Amazon,” they wrote, urging employees to help “make these experiences truly exceptional”.

Amazon expanded Kiro’s availability globally last week, adding new features as it seeks wider internal adoption.

Reuters noted that Codex, Cursor and Claude Code have become popular among engineers for rapid application development. Cursor was recently valued at nearly $30 billion following a funding round. Amazon has previously tightened controls around external tools: in October, the company updated its guidance on Codex to “Do Not Use” after a six-month review. Claude Code briefly received the same designation before Amazon reversed the decision after a reporter inquiry, Reuters said.

Amazon confirmed the authenticity of the latest memo, while Anthropic, OpenAI and Cursor did not respond to requests for comment.

The tougher internal stance underscores Amazon’s determination to accelerate its AI strategy and bring more development activity onto its own stack. Further product updates and closer integration between AWS services and Kiro as the company seeks to compete more directly in enterprise AI tooling next year.